Railway traffic controlling apparatus



Sept. 13, 1932. A. T. JOHNSTON RAILWAY TRAFFIC CONTROLLING APPARATUSFiled Sept. 5, 1930 INVENTOR'.

N, QRNE? Patented Sept. 13, 1932 PATENT OFFICE ALLAN '1. JOHNSTON, OFMOUNT LEBANON, SWITCH & SIGNAL COMPANY, OF SWISS PENNSYLVANIA 1Application med September My invention relates to railway trafficcontrolling apparatus, and has for an ob]ect the protection of suchapparatus from currents of such magnitude as might be injurious.

I will describe one form of apparatus cmhodying my invention, and willthen point out the novel features thereof in claim.

The accompanying drawing is a diagram matic view showing one form ofapparatus embodying my invention.

Referring to the drawing, the reference character A designates a railwayswitch which is actuated by an electric motor M which in form here showncomprises an armature 1 and a field 2. Operatively connected with theswitch are cut-out controllers 3 and 4; cut-out controller 3 is closedat all times except when the switch occupies its extreme reverseposition, and cut-out controller 4 is closed at all times except whenthe switch occupies its extreme normal-position.

The motor M is controlled in part by a circuit controller designated ingeneral by the reference character P, and which is in turn controlled ba pole changer L which may be incorporate locking machine. The circuitcontroller P comprises an electroma net 9 made up of two windings 9 and9" an a polarized winding 10 which is preferably provided with apermanently magnetized core 11. Pivotally attached to the core 11 is anarmature 12 which is therefore polarized by flux from the permanentmagnet core 11 at such times as winding 10 is not carrying current. Itfollows that when the electromagnet 9 is supplied with current of onepolarity the armature 12 will be swung in a clockwise direction, butthat when current of the opposite polarity is sup plied to electromagnet9 the armature will be swung in the opposite direction. The armature 12controls three movable contact yokes 13, 14 and 15 through suitablelinkage in such manner thatthe yokes occupy their right-hand positionswhen the armature is swung to the left, and vice-verse.

The reference character-B designates a neutral magnet which controls apivoted armature 17, the lower end of which projects into the path ofmovement of a portion of armain a switch lever of an inter-PENNSYLVANIA, ASSIGNOR TO THE UNION VALE, PENNSYLVANIA, A CORPORATION OFRAILWAY rnarrrc CONTROLLING "ran-Rim 3, 1930. Serial No. 479,456.

ture 12 to prevent the reversal of the armature when the neutral magnetB is decnergized. Pivotally attached to the armature 17 is a link 19provided with a slot 42 which at times engages a pin 43 in a rocker armwhich carries a contact 20. Vhen magnet 13 is decncrgized the link 19moves the rocker arm 70 against the bias exerted by spring 41 into aposition in which the contact 20 connects wire 33 with wire 34. Whenneutral magnet B is energized, however, the spring 1 1 urges the rockerarm 70 into a position wherein the contact between wires 33 and 351 isinterrupted. As shown in the drawing, the

switch A occupies its normal position; the x neutral magnet B isdcenergized thereby locking armature 12 of circuit controller P in itsleft-haud position; and the pole-changer L on the switch lever occupiesits normal position.

The apparatus thus far referred to is illustrated and described inUnited States Letters Patent No. 1,722,364, granted to Henry S. Young onthe 30th day of July, 1929, for railway traffic controlling apparatus.

The reference character R designates an automatic thermal overloadcircuit breaker. Vindings 22 and 23 of the circuit breaker R are shuntedrespectively by resistors T and T which have a large resistivitytemperature constant. A continuous current flowing through resistor T orT will cause it to heat, increasing its resistance, with consequentincrease in the voltage across the coil winding 22 or hen the voltage isof sufficient value the circuit breaker will operate to open contact33-34 by armature 21 being attracted,

that is, detent 57 will lift the link 19 and the spring 44 will open thecontact between wires 33 and 34. The circuit breaker R is made"slow-releasing to prevent the possibility of the'h'eavy startingcurrent causing the circuit .to be opened at each operation. Circuitbreaker R consists of two magnets, one having a core 24 and the otherhaving a core 25, with armatures which are pivoted separately, but arejointly connected to a tripping arm 27. When the motor circuit is firstclosed, there is a heavy surge of current through it, due to the lowresistance of the motor and the fact that the counter electromotiveforce has not had an opportunity to build up, but as soon as the motorspeeds up the counter electromotive force approaches the value of theimpressed electromotive force and therefore the current is reduced tothe normal operating current. To prevent the momentary currentabove-mentioned from tripping the breaker every time the motor starts,core 25 has a winding H which is connected in series with the winding Hon core 24. This double winding, il -H function like a transformer.lVhen the first surge of current passes through the coil winding, 22 or23, there is induced in winding H an electromotive force generallyproportionate to the rapidity of the rise of the current in the motorcircuit. This electromotive force is impressed on the winding H,,sending a current through it which assists in holding the armature 20against the pole face 26. \Vhen the current ceases to change in value,no more current will be induced in the winding H and hence there will beno magnetic attraction of the armature 20 by the secondary magnet 24. Ifthe current in the motor circuit continues at too great a value, theprimary magnet is then unopposed by the secondary magnet and the circuitbreaker operates as before described. It the surge of current is reducedto normal within a specified time. the attraction of the armature 21will not be sufficient to overcome the spring 52 and the motor circuitwill not be opened. Two resistors T and T are used, one for eachdirection of the motor. to allow the return of switch A to its originalposition without waiting for the resistor, just used, to cool. Vhen thepole-changer L is first reversed, proper contacts close and the currentflows in such a direction through the circuit controller P that thearmature 12 is reversed from the normal position shown in the diagram,thus the yokes 13, 14: and 15 are moved to the left by the linkage. Themotor circuit is now from terminal BH of a source of current, throughwire 7, wire 18, wire 33. contact 20, wire 3.4 wire 19, contact 29, wire35, armature 1. wire 32, contact 31, wire 36. resistor T and in parallelthrough winding cut-out controller 3, held 2, wire 37, to terminal CH ofthe same source of current. When the switch is returning to the normalposition from the reverse, cut-outcontroller 5 is open, cut-outcontroller 4 is closed and the motor circuit is from terminal EH,through wire 7 wire 18, wire 33, contact 20, wire 3%., wire 19, contact28, wire 32, armature 1, wire 35, contact 30, wire 38, resistor T 1 andin. parallel through winding 23, cutout controller 4, iicld 2-, wire 37and to terminal CH.

The automatic thermal overload circuit breaker is characterized by thefact that it will introduce time delay which will trip the breaker afterallowing the clutch on the claim without departing from the spirit andscope of my invention.

Having thus described my invention, what I claim is:

In combination, an electric motor, two circuits for said motor eachincluding a resistor having a high positive temperature coefiicient,means for supplying current to one of said circuits or the other tocause operation of the motor in one direction or the other, a circuitbreaker for controlling the supply of current to said motor and havingtwo tripping windings in inductive relation with each other connectedacross the terminals of said two resistors respectively, whereby whencurrent is supplied to one of said motor circuits the tripping windingassociated with the other motor circuit will be closed through itsresistor for decreasing rapid current variations in the other trippingwinding, a third winding in inductive relation to each of said trippingwind- ,ings, and a holding winding for said circuit breaker connectedwith said third winding.

In testimony whereof I atfix my signature.

ALLAN T. JOHNSTON.

